To achieve this re-binning the latitude of each zonal cell was converted into a 360-degree equivalent meridional angle with the North Pole 90-degree latitude as the zero-angle datum. For this meridional great circle, the far side surface latitudes are calibrated between 0 and 180 degrees and the near side (sun facing) latitudes are calibrated between 180 and 360 degrees. This data re-organisation ensures that the planet’s zonal latitudes track the seasonal axial tilt illumination, consequently only lit surface latitudes were used to compute average daytime temperatures and correspondingly only dark surface latitudes were used to compute average nighttime temperatures (Table 5).
The MY29 temperature data are organised by 5-degree wide latitudinal zones across the full surface area of the Martian globe. Because of the standard geometric effect on surface area of zonal latitude bands, whereby zonal latitude area has a maximum value at the equator and decreases towards the poles, it is necessary to compute the temperature data using an areal weighted algorithm. This process ensures that high-latitude polar zones of small surface area are not overrepresented in the calculation of global temperature averages.
In addition to the areal weighted averages of global temperature, similar calculations were made of the average tropopause height for the two polar and one tropical convection cell. Using these tropopause heights as the upper boundary, a surface to tropopause lapse rate was calculated for each zonal latitude component of the planetary meridional atmospheric transect. (Table 5).